Impact tool with hammer rotatable and axially movable within the motor



Nov. l0, 1964 D HozA 3,156,334

M. IMPACT TOOL WITH HAMMER ROTATABLE AND AXIALLY MOVABLE WITHIN THE MOTOR Filed May 16. 1961 4 Sheets-Sheet 1 Nov. 10, 1964 M D HozA 3,156,334

IMPACT TOOL WITH lllAMMER ROTATABLE AND AXIALLY MOVABLE WITHIN THE MOTOR Filed May 16. 1961 4 Sheets-Sheet 2 Nov. 10, 1964 D H 3,156,334

M. OZA IMPACT TOOL W HAMMER ROTATABLE AND AXIALLY MOV E WITHIN THE MOTOR Filed May 16, 1961 4 Sheets-Sheet 3 Mar f// /aza INVENToR.

Nov. l0, 1964 M. D. HOZA IMPACT Tool. wITH HAMMER ROTATABLE AND AXIALLY MovABLE WITHIN THE MoIoR 4 Sheets-Sheet 4 Filed May 16. 1961 Mar/f7 Hoz@ INVENTOH @HIM l du-lak 11p-Hun., if?,

Arran/wsrf United States Patent O 3,156,334 IMPACT TOOL WITH HAMMER RTATABLE AND AHALLY MQVABLE WITHHN Til@ MOR Martin D. Hoza, Houston, Tex., assigner to Reed Relier Bit Company, Houston, Tex., a corporation of Texas Filed May 16, 1961, Ser. No. 110,384 9 Claims. (Cl. 192-30.5)

This invention relates generally to a fluid operated rotary impact tool adapted to rotate and provide impact blows to screws, nuts, bolts and the like.

. It is an object of this invention to provide a new and improved portable impact tool which will deliver great impact torque for its weight and size.

Another object is to provide a new and improved lightweight impact tool which is simple in construction and easy to service.

Another object is to provide a new and improved irnpact wrench structure wherein the mass of a motor is closely coupled with a hammer to enhance the effective impact forces.

Another object is to provide a new and improved structure for an impact wrench wherein the hammer is carried by the driving motor, and a portion of the hammer telescopes within the motor.

Another object is to provide a new and improved impact tool having hammer and anvil jaws and means to properly align and engage such jaws for impact.

Another object is to provide a new and improved lubricatlng system for a pressure fluid operated tool.

Other objects will become apparent from the following description and the accompanying drawings, in which:

FIG. 1 is a longitudinal sectional view of an impact tool showing the position of various parts prior tolthe time of impact.

FIG. 2 is a longitudinal sectional view of the tool showing the position of various parts at the time of impact.

FIG. 3 is an enlarged sectional view taken along line 3-3 in FIG. l.

Fl. 4 is a fragmentary view taken along line 4 4;- in

FIG. 5 is an exploded perspective view of the hammer and anvil, the cam element and cam roller, and the shaft which extends between the anvil and cam element.

Referring to the drawings, particularly to FIGS. 1 and 2, as elastic pressure fluid operated impact tool is shown comprising a housing 1 enclosing a rotary vane-type motor 2. The motor 2 has a rotor 3 having slidable vanes 4 extending between a front bearing plate 5 and rear bearing plate 6. The rotor 3 is rotatably mounted on bearing assemblies 7 and S. The rotor 3 has a shoulder 9 against which is disposed a thrust washer lll. A roller bearing assembly 11 is disposed between the thrust washer it? and a compression spring 12 which extends between the bearing assembly l1 and the spring cup 13 resting on the housing web 14 to urge the motor 2 towards the front of the tool to take up end play. Suitable static seals l5 and 16 are provided to alleviate the loss of pressure lluid from the motor.

A rotatable anvil 22 is disposed in the front end of the tool, and is provided with a suitable bearing 23 which may be supplied with lubricant through the plug opening 24. The anvil 22 has a reduced end 25 which extends through bearing 23 and from the housing 1, and is provided With suitable driving ilats 26, or the like, which` drive a socket 27 which is adapted to engage and rotatably drive a work piece such as a bolt 28. The anvil 22 has an enlarged portion 2g interiorly of the tool. One or more driven jaws ,30 extend axially of the enlarged anvil portion Y rEhe rotor 3 has a bcrel therethrough, a portion of 3,155,334 Patented Nov. l0, 196@ ICC which is splined as shown at 32. A hammer 33 has an enlarged portion 3d extending forwardly of the motor 2, and is provided with one or more driving jaws 35 arranged in confronting relation with driven jaws Sil of the anvil 22. The hammer 33 has a reduced splined portion 36 which registers with and telescopes within the splined portion 32 of the rotor 3. A cam element 37 is provided in the `bore 3l in axial alignment with the end di; of the reduced hammer portion 36. A roller bearing assembly 39 may be employed between the end 3S of the hammer 33 and the cam element 37.

The rotor 3 has a radial bore 53 into which is disposed a roller shaft 54 having a reduced end 55 upon which is mounted a cam roller 56. The roller shaft 54 and the roller 56 are maintained within the bore 53 by means of a spring retainer 57 at the radially outer end, and at the inner end by engaging a reduced cylindrical portion 53 of the cam element 37.

A rotatable shaft 59 extends between the anvil 22 and the cam element 37. The forward end of the shaft S9 has a cylindrical portion 60 rotatable within a bore 61 of the anvil 22. The shaft 59 has a reduced portion 62 extending through a bore 69 of the hammer 33. The end of the shaft 59 is provided with flats 63. A shoulder 65 is provided on the shaft 59 and an internal shoulder do is provided on the hammer 33. TheI shaft 59 has radial lobes 6'7 serving to engage axially the anvil 22, and to rotatably drive the jaws 30 of the anvil 2.2, and to provide for limited angular movement therebetween. A compression spring 64 is disposed between the shoulder 65 and the internal shoulder 66 to urge apart the anvil 22 and the hammer 33.

The housing l has a handle portion l7 which carries a trigger l5 which, when in the position shown in FIG. 2, serves to open the inlet valve l@ to admit pressure fluid into the tool from a suitable pressure source through a swivel connection 2&3. A spring 21 urges the valve 19 to the closed position as shown in FIG. l.

The housing l. has a fluid passageway 4t? which coinmunicates with the inlet valve 19 and directs pressure fluid through the passageway il of the reversing valve 42. The reversing valve may be positioned to supply pressure fluid to either of ports 43 or 44, and thence through passagew ys 45 or di? to the motor 2 to effect clockwise or counterclockwise rotation thereof as desired. The pressure iluid is then exhausted through ports 47.

The housing l has a closed lubricant reservoir 48 into which lubricant may be supplied through the threaded opening 49 which is then closed with a threaded plug 5d. A porous plug 5l extends between the reservoir 4S and the fluid passageway 4t), and serves to admit pressure fluid into the lubricant reservoir ad as the tool is being run. The iluid pressure in reservoir 4S forces a portion of lubricant through the porous plug 5l into the passageway di) as the fluid pressure in such passageway is reduced when the tool is stopped. Thus lubricant is carried by the pressure iluid throughout the tool during the normal operation thereof. In other words, when the air to the tool is shut oil and the tool is being transferred from say one workpiece to another, the fluid pressure in the passageway lil will be reduced to or about equal to atmospheric pressure; then the pressure fluid within the reservoir 48 will force a portion of the lubricant out through the porous plug 5l into the. passageway 45B. rl`hus, when the tool is re-started, the incoming air moving through passageway ill and the tool housing l will have such lubricant entrained therein to convey it throughout the tool in the form of a mist.

The flats 63 of the shaft 59 are adapted to engage with the walls of a slot 63 in the cam element 37 (FIG. 5) to provide a driving connection between the shaft Si? and the cam element 3'7", and to provide for limited langular movement therebetween. The cam element 37 is provided with a circular cam surface lil which is adapted to engage with the cam roller 56 on the roller shaft 54 which is carried by the rotor 3.

In operation, the trigger 13 opens thel valve i9 whereupon elastic pressure fluid, such as compressed air, is introduced into the passageway lil and through the passageway di of the reversing valve 42, through port 43 and mto passageway 45 to the motor 2 for clockwise rotation. As the motor begins to turn, the cam roller 56 engages an inclined face 7l to rotate the cam element 37. The walls of the slot 63 in turn engage the flats 63 of the shaft 59, and the lobes 67 or the shaft 59 engage the jaws of the anvil 22, to angularly position the jaws Sil and 3S and to run up a work piece such as the bolt 23. As long as the resistance to rotation of the anvil Z2 is relatively light, the work piece is driven as just described with the jaws 30 and 35 being held axially apart by the spring 64. During such operation, with an air pressure supply of about 90 p.s.i., the speed of the tool is about 3500 rpm.

As the work piece is tightened, the anvil 22 resists rotation whereupon the cam roller 56 proceeds up the in- Cline 71 of the cam element 37 to compress the spring 6d, and to move the hammer 33 forwardly to engage the anvil 22. Before the hammer jaws strike the anvil jaws 3b, the cam roller S passes over the crest 72 of the cam element 37 thereby momentarily freeing the cam roller 55 from operative association with the cam element 37. The inertia of the hammer 33 maintains the hammer jaws 3S in engagement with the anvil jaws 3G until the combined energy of the motor 2 and the hammer 33 are delivered to the anvil 22. After such impacting, the spring 64 disengages the hammer jaws 35 from the anvil jaws 3d, thus allowing the motor 2 and hammer 33 to accelerate for the next impact. The cam surface '/'l is again engaged by the roller 56 to angularly position the hammer jaws 35 and the anvil jaws 30, and the impact operation just described is repeated. During impacting, the tool operates at approximately 600 rpm. and impacts once per revolution.

During the run up of the work piece 23, as above described, the anvil 22 is maintained tight to the Work thus permitting the transmission of a maximum amount of energy to the work during impact.

The hammer 33 may have a plurality of holes 73 which communicate with the bore 69. Thus as the hammer 33 reciprocates within the motor 2, lubricant is distributed to the shaft 59 and to the splined portions 32 and 36.

Because the hammer 33 is telescoped within the motor 2, the motor weight is coupled directly to the hammer weight, thus providing a large eEective mass for impacting the anvil 22.

This invention is not limited to the embodiment shown. Various changes within the scope of the following claims will be apparent to those skilled in the art.

I claim:

1. An impact tool comprising a housing, an elastic pressure fluid operated motor, the said housing having uid passageways communicating with said motor, a rotatable hammer having an enlarged end and a reduced end, the said reduced end being coaxial with and telescoped within said motor, the said enlarged end of said hammer having one or more driving jaws, a rotatable anvil having one or more driven jaws confronting with said driving jaws, means urging the said hammer and anvil axially apart, a cam element abutting the reduced end of said hammer, a rotatable shaft extending between the said anvil and cam element, a radially disposed cam roller carried by said motor and engageable with the said cam element, the forward end of said shaft having a lobe engageable with the said driven anvil jaws, the said cam element having a siot therein, the rearward end of said shaft having flats drivingly c-ngageable within said slot, the said cam roller adapted to move the cam element and hammer axially to effect engagement of the said driving and driven jaws upon a predetermined resistance to rotation of the said anvil, the said shaft lobe and flats adapted to maintain a predetermined angular relation between the said anvil and cam element, the said housing having a closed lubricant reservoir, a porous plug extending between the interior of said reservoir and one of the said fluid passageways, the said porous plug adapted to admit pressure iiuid into the reservoir during operation of the tool, and to supply a portion of the lubricant from the reservoir into the said passageway upon suspension of such tool operation.

2. An impact tool comprising a housing, an elastic pressure huid operated motor, the said housing having fluid passageways communicating with said motor, a rotatable hammer having an enlarged end and a reduced end, the said reduced end being coaxial with and telescoped within said motor, the said enlarged end of said hammer having one or more driving jaws, a rotatable anvil having one or more driven jaws confronting with said driving jaws, means urging the said hammer and anvil axially apart, a cam element abutting the reduced end of said hammer, a rotatable shaft extending between said anvil and cam element, cam means carried by said motor and engageable with the said cam element, the forward end of said shaft engageable with the said anvil, the rearward end of said shaft engageable with said cam element, the said cam means adapted to move the cam element and hammer axially to effect engagement of the said driving and driven jaws upon a predetermined resistance to rotation of the said anvil, the said shaft adapted to maintain a predetermined angular relation between the said anvil and cam element.

3. An impact tool comprising a housing, a motor, a hammer means, a portion of said hammer means being slidable within said motor, a rotatable anvil, said hammer means having a driving jaw and said anvil having a driven jaw, means adapted to move said hammer means toward said anvil to effect engagement of the jaws of said hammer means and anvil upon a predetermined resistance to rotation of the said anvil, and means effective to provide a given angular relationship between the said hammer means and anvil jaws to position said jaws for impacting upon operation of said tool.

4. An impact tool comprising a rotatable hammer having one or more driving jaws, a rotatable anvil having one or more driven jaws, a motor, a portion of said hammer being within said motor, and means within said motor to cause said motor to rotate said hammer and to permit the hammer to reciprocate axially, means urging the said hammer and anvil jaws axially apart, a rotatable shaft extending between the said anvil and the said hammer and adapted to maintain a predetermined angular relationship between the said hammer and anvil, means effective in response to a predetermined resistance to rotation of the anvil to move the said hammer and anvil jaws into engagement.

5. An impact tool comprising a motor, a hammer rotatably carried by and slidable within said motor, means within said motor to cause said motor to rotate said hammer and to permit at least a portion of said hammer to reciprocate axially, the said hammer having at least one driving jaw, a rotatable anvil having at least one driven jaw, yieldable means urging said hammer and anvil axially apart, cam means acting in opposition to said yieldable means to move the hammer to effect engagement of the hammer and anvil jaws, and means connecting said cam means to said anvil to effect a predetermined angular relation between said hammer jaw and said anvil jaw upon operation of said tool.

6. An impact tool comprising a motor, a hammer, means whereby said hammer is rotatably carried by said motor with at least a portion of said hammer being slidable axially within said motor, the said hammer having at least one driving jaw, a rotatable anvil having at least one driven jaw, and means adapted to effect engagement of the said hammer and anvil jaws upon operation of said tool to impart the energy of the rotating motor and hammer to the anvil.

7. An impact tool comprising a motor, a hammer rotatably carried by and slidable within said motor, means within said motor to cause said motor to rotate said hammer and to permit at least a portion of said hammer to reciprocate axially, the said hammer having at least one driving jaw, a rotatable anvil having at least one driven jaw, cam means acting to move the hammer to eect engagement of the hammer and anvil jaws, and means connecting said cam means to said anvil to effect a predetermined angular relation between said hammer jaw and said anvil jaw upon operation of said tool.

8. An impact tool comprising a motor, a hammer yand an anvil, the said hammer being rotatably carried by and slidable Within said motor, means to cause said motor to rotate said hammer and to permit at least a portion of said hammer to reciprocate axially, and means to cause said hammer to strike said anvil and impart the energy of the rotating motor and hammer to the anvil.

9. An impact tool comprising a motor, a hammer rotatably carried by said motor, and an anvil, a portion of said hammer being radially enlarged and disposed near said anvil, another portion of said hammer being axially elongated and slidable within said motor, spline means to cause said motor to rotate said hammer and to permit said hammer to reciprocate axially, and means to cause said enlarged portion of said hammer to strike said anvil and impart the energy of the rotating motor and hammer to the anvil.

References Cited bythe Examiner UNTED STATES PATENTS OTHER REFERENCES Ingersoll-Rand Instruction and Repair Part List Form 5857, 2nd edition, April 1960 (15 pp.).

DAVID I. WILLIAMOWSKY, Primary Examiner.

THOMAS J. HICKEY, Examiner. 

8. AN IMPACT TOOL COMPRISING A MOTOR, A HAMMER AND AN ANVIL, THE SAID HAMMER BEING ROTATABLY CARRIED BY AND SLIDABLE WITHIN SAID MOTOR, MEANS TO CAUSE SAID MOTOR TO ROTATE SAID HAMMER AND TO PERMIT AT LEAST A PORTION OF SAID HAMMER TO RECIPROCATE AXIALLY, AND MEANS TO CAUSE SAID HAMMER TO STRIKE SAID ANVIL AND IMPART THE ENERGY OF THE ROTATING MOTOR AND HAMMER TO THE ANVIL. 